Root nodules which are present in plants are meant for fertilizers and are found in/on

Options

A. Certain leguminous plants
B. Casuarina
C. Almus
D. All of the above

Answer

**Step-by-Step Solution:**

1. **Understanding Root Nodules**: Root nodules are specialized structures found in the roots of certain plants. They play a crucial role in the process of nitrogen fixation, which is essential for plant growth as nitrogen is a vital nutrient.

2. **Nitrogen Fixation**: The process of nitrogen fixation is primarily carried out by specific bacteria that have the ability to convert atmospheric nitrogen into a form that plants can use. This process is known as biological nitrogen fixation.

3. **Types of Plants with Root Nodules**:
- **Leguminous Plants**: The most common plants that form root nodules are legumes. These plants have a symbiotic relationship with nitrogen-fixing bacteria, particularly the genus Rhizobium. When these bacteria infect the roots of leguminous plants, they form root nodules that facilitate nitrogen fixation.
- **Non-Leguminous Plants**: Some non-leguminous plants can also form root nodules. For example, the genus Casuarina is known to have species that can form root nodules.
- **Alnus**: Another example is the plant genus Alnus, which forms root nodules with the help of the bacteria Frankia alni.

4. **Conclusion**: Therefore, root nodules are found in certain leguminous plants, as well as in some non-leguminous plants like Casuarina and Alnus. These nodules are essential for nitrogen fixation, which helps in providing fertilizers to the plants.

**Final Answer**: Root nodules which are present in plants are meant for fertilizers and are found in certain leguminous plants, Casuarina, and Alnus.

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